Skyrmion diode and method of manufacturing the same

ABSTRACT

The present disclosure provides a skyrmion diode using skyrmions as information carriers. The skyrmion diode includes a magnetic body and a conductive body. The magnetic body has a skyrmion which is used as information carrier. The conductive body is disposed on or under the magnetic body. The conductive body includes a Dzyaloshinskii-Moriya interaction (DMI) region and a defect region. The DMI region is provided to induce DMI in a region of the magnetic body corresponding to the DMI region by the spin-orbit coupling of the conductive body and magnetic moments of the magnetic body. The defect region is provided to prevent the DMI from being induced in a region of the magnetic body corresponding to the defect region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 15/431,488 filed on Feb. 13, 2017, which claims the benefit ofKorean Patent Application No. 10-2016-0026930, filed on Mar. 7, 2016,which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a skyrmion diode, more particularly,to a skyrmion diode using skyrmions as information carriers and a methodof manufacturing the skyrmion diode.

BACKGROUND

As well known in the art, semiconductor technology so far has beendeveloped according to Moore's law. However, quantum phenomena occur asfeature sizes of semiconductor devices are continuously scaled down, andtherefore, a design rule that has been previously employed has to bechanged.

New challenges and approaches have been attempted to break away fromsilicon-based device concepts in consideration of, e.g., heat problemsdue to drastic increases in power consumption, slowing of informationprocessing speed, and rapid increase in manufacturing equipment andprocess costs. In this connection, various studies and researches havebeen devoted to overcome the current technical limitations.

For example, conventionally, there is disclosed ‘a method of generatingand erasing skyrmion and magnetic element’ in Japanese PatentApplication Publication No. 2014-175417 (published on Sep. 22, 2014).

In this conventional case, corners are provided in a magnetic bodyhaving a skyrmion phase, and skyrmion is generated by applying currentacross the corners in a state where a magnetic field is applied in apredetermined intensity range.

However, since the magnetic body has to be formed in a shape having thecorners, a limited manufacturing process such as a slurry molding canonly be used. Further, electrical characteristics vary depending on theshape, size or position of the corner, but it is difficult to perform afine adjustment for the electrical characteristics, which isproblematic.

SUMMARY

In view of the above, the present disclosure provides a skyrmion diodeusing skyrmions as information carriers without providing corners in amagnetic body having the skyrmions and a method of manufacturing theskyrmion diode.

In accordance with an aspect of the present disclosure, there isprovided a skyrmion diode including a magnetic body and a conductivebody. The magnetic body may have a skyrmion which is used as aninformation carrier. The conductive body may be disposed on or under themagnetic body. The conductive body may include a Dzyaloshinskii-Moriyainteraction (DMI) region and a defect region. The DMI region is providedto induce DMI in a region of the magnetic body corresponding to the DMIregion by spin-orbit coupling of the conductive body and magneticmoments of the magnetic body. The defect region is provided to preventthe DMI from being induced in a region of the magnetic bodycorresponding to the defect region.

Further, spin-polarized current may be supplied to at least one of themagnetic body and the conductive body. The defect region may be formedby forming a notch portion at a side portion of the conductive body. Thenotch portion may have a semicircular shape, a triangular shape or arectangular shape.

In accordance with another aspect of the present disclosure, there isprovided a method of manufacturing a skyrmion diode, the methodincluding: forming a magnetic body including a skyrmion, which is usedas an information carrier; forming a conductive body having spin-orbitcoupling on or under the magnetic body; and forming a defect region in apart of the conductive body, which prevents Dzyaloshinskii-Moriyainteraction (DMI) induced by the spin-orbit coupling and magneticmoments of the magnetic body from being induced in a region of themagnetic body corresponding to the defect region.

Herein, the defect region may be formed by forming a notch portion at aside portion of the conductive body. The notch portion may have asemicircular shape, a triangular shape or a rectangular shape.

The skyrmion diode according to the aspects of the present disclosureemploys a conductive body including the DMI region for inducing the DMIin the magnetic body and the defect region for preventing the DMI frombeing induced in the magnetic body. Therefore, the skyrmion is used asan information carrier without providing corners in the magnetic body.

With such configuration, various manufacturing processes can beintroduced since the conductive body can be easily manufactured invarious shapes as compared with the magnetic body. Further, there can beeasily performed a fine adjustment of the defect region in which theelectrical characteristics are varied depending on its shape, size orposition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of an exemplary skyrmion diodeaccording to one embodiment.

FIG. 2 is a perspective view of an exemplary conductive body accordingto one embodiment.

FIG. 3 is a perspective view of an exemplary conductive body accordingto another embodiment.

FIG. 4 is a flow chart illustrating an exemplary method of manufacturingthe skyrmion diode according to one embodiment.

FIG. 5 is a graph showing the diode characteristics.

DETAILED DESCRIPTION

The advantages and features of the present disclosure and the method foraccomplishing them will be clearly understood from the followingdetailed description of the embodiments taken in conjunction with theaccompanying drawings. However, the present disclosure is not limited tothose embodiments disclosed herein below, but may be implemented invarious forms. It should be noted that the embodiments are provided tomake a full disclosure of the present disclosure and also to allow thoseskilled in the art to know the full scope of the present disclosure.Therefore, the present disclosure will be defined only by the scope ofthe appended claims.

In the following description, well-known functions and/or constitutionswill not be described in detail if they would unnecessarily obscure thefeatures of the present disclosure in unnecessary detail. Further, theterms to be described below are defined in consideration of theirfunctions in the embodiments of the present disclosure and may varydepending on user's or operator's intention or practice. Accordingly,the definition may be made on the basis of the content throughout thespecification.

Hereinafter, preferred embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is an exploded perspective view of an exemplary skyrmion diodeaccording to one embodiment. FIG. 2 is a perspective view of anexemplary conductive body according to one embodiment. FIG. 3 is aperspective view of an exemplary conductive body according to anotherembodiment. As shown in FIGS. 1 to 3, a skyrmion diode 100 includes amagnetic body 110 and a conductive body 120.

The magnetic body 110 is disposed on or under the conductive body 120and has a skyrmion serving as an information carrier.

When spin-polarized current is supplied to at least one of the magneticbody 110 and the conductive body 120, spin-transfer torque is generatedto move the skyrmion. In addition, since the conductive body 120 hasstrong spin-orbit coupling, spin-orbit torque can be generated by a spinHall effect or a rashba effect to thereby move the skyrmion.

The conductive body 120 includes a Dzyaloshinskii-Moriya interaction(DMI) region 121 for inducing DMI in a region of the magnetic body 110corresponding to the DMI region 121 by magnetic moments of the magneticbody 110 and a spin-orbit coupling of the conductive body 120. Further,the conductive body 120 includes a defect region 122 to prevent the DMIfrom being induced in a region of the magnetic body 110 corresponding tothe defect region 122 (that is, a region of the magnetic body 110 otherthan the region corresponding to the DMI region) in spite of themagnetic moments of the magnetic body 110 and the spin-orbit coupling ofthe conductive body 120.

The defect region 122 may be formed by forming a notch portion at a sideportion of the conductive body 120. For example, the notch portion isformed by cutting away a part of a longitudinal side portion of theconductive body 120 having a rectangular shape and is positioned on aleft longitudinal side portion or a right longitudinal side portion ofFIG. 1 depending on the diode characteristic of e.g., a forwarddirection or a reverse direction. Further, the notch portion may beformed in a semicircular shape as shown in FIG. 1 or a triangular shapeas shown in FIG. 2. Alternatively, the notch portion may be formed in arectangular shape as shown in FIG. 3.

FIG. 4 is a flow chart illustrating an exemplary method of manufacturingthe skyrmion diode according to one embodiment, wherein the magneticbody 110 is formed first.

In the method, a step S210 of forming the magnetic body 110 is carriedout first. For example, the magnetic body 110 can be formed by using aprocess such as a slurry molding. An alloy-based magnetic material suchas a cobalt-iron (CoFe) alloy, a cobalt-iron-boron (CoFeB) alloy or thelike, or a Heusler alloy-based magnetic material such as acobalt-ferrosilicon (Co₂FeSi) alloy, a cobalt-manganese-silicon(Co₂MnSi) alloy or the like can be used to form the magnetic body 110.

Then, a step S220 of forming the conductive body 120 on or above themagnetic body 110 is carried out. For example, the conductive body 120can be formed by using a process such as a sputtering, a molecular beamepitaxy (MBE), an atomic layer deposition (ALD), a pulse laserdeposition (PLD), or an E-beam evaporator. A heavy metal such asplatinum (Pt), tantalum (Ta), iridium (Ir) or the like may used to formthe conductive body 120.

Next, a step S230 of forming the defect region 122 in the conductivebody 120 is carried out to prevent the DMI from being induced in theregion of the magnetic body 110 corresponding to the defect region 122in spite of the magnetic moments of the magnetic body 110 and thespin-orbit coupling of the conductive body 120. For example, the defectregion 122 may be formed by forming a notch portion at a side portion ofthe conductive body 120 through a photo etching process. The notchportion may be formed in, e.g., a semicircular shape, a triangularshape, or a rectangular shape. The electrical performance of theskyrmion diode 100 may be controlled by adjusting at least one of theshape, size and position of the notch portion.

The skyrmion diode 100 according to one embodiment includes the magneticbody 110 disposed on or under the conductive body 120, and a skyrmion inthe magnetic body 110 can be moved by spin polarized current. Further,since the skyrmion moves only through the region where the DMI isinduced, the region of the magnetic body 110 corresponding to the DMIregion 121 serves as a waveguide. When the skyrmion moving through thewaveguide reach the region of the magnetic body 110 where no DMI isinduced due to the defect region 122, there occurs an interaction whichcauses the skyrmion to selectively turn around the defect region 122 ina specific direction, e.g., in a clockwise or counterclockwise directionbased a spin orientation. Based on this interaction, the diodecharacteristics can be realized by allowing current-induced skyrmion toflow and move in one direction.

FIG. 5 is a graph showing the diode characteristics. A horizontal axis(X-axis) indicates conduction electron velocity Vs (m/s) and a verticalaxis (Y-axis) indicates skyrmion velocity Vd (m/s). If the intensity ofthe current corresponding to the conduction electron velocity is largerthan that of a critical current, the skyrmion becomes an ON state whereit can pass by the defect region. If the intensity of the currentcorresponding to the conduction electron velocity is smaller than thatof the critical current, the skyrmion becomes an OFF state where itcannot pass by the defect region. Further, as shown in FIG. 5, it can beseen that the intensity of the critical current in the forward directionis different from the intensity of the critical current in the reversedirection.

The explanation as set forth above merely provides a technical idea ofthe present disclosure, and it will be understood by those skilled inthe art to which the present disclosure belongs that various changes andmodifications may be made without departing from the scope of thecharacteristics of the present disclosure. Therefore, the embodimentsdisclosed in the present disclosure are not used to limit the technicalidea of the present disclosure, but to explain the present disclosure,and the scope of the technical idea of the present disclosure is notlimited to these embodiments.

The scope of protection of the present disclosure should be construed asdefined in the following claims, and all technical ideas that fallwithin the equivalent technical idea of the present disclosure areintended to be embraced by the scope of protection of the presentdisclosure.

What is claimed is:
 1. A method of manufacturing a skyrmion diode, themethod comprising: providing a magnetic body including a skyrmionserving as an information carrier; and disposing a conductive body on orunder the magnetic body, wherein the conductive body includes a notchportion at one side portion thereof and a remaining portion other sidethan the notch portion, and wherein the notch portion of the conductivebody serves as a defect region for preventing a Dzyaloshinskii-Moriyainteraction (DMI) from being induced in a region of the magnetic bodycorresponding to the notch portion, wherein the remaining portion of theconductive body serves as a DMI region for inducing the DMI in a regionof the magnetic body corresponding to the remaining portion byspin-orbit coupling of the conductive body and magnetic moments of themagnetic body, wherein the skyrmion in the magnetic body moves by aspin-polarized current only through the region of the magnetic bodycorresponding to the DMI region of the conductive body and the skyrmionselectively turns around the region of the magnetic body correspondingto the defect region of the conductive body in a direction based on aspin orientation to allow the skyrmion to have diode characteristics,wherein the magnetic body is provided without having the notch portion,and wherein the magnetic body covers the entire conductive body.
 2. Themethod of claim 1, wherein the spin-polarized current is supplied to themagnetic body.
 3. The method of claim 1, wherein the spin-polarizedcurrent is supplied to the conductive body.
 4. The method of claim 1,wherein the spin-polarized current is supplied to both of the magneticbody and the conductive body.
 5. The method of claim 1, wherein thenotch portion has a semicircular shape.
 6. The method of claim 1,wherein the notch portion has a triangular shape.
 7. The method of claim1, wherein the notch portion has a rectangular shape.